# std.crypto: Optimize SHA-256 intrinsics for AMD x86-64 · gitcafe/zig

[View on GitCafe](https://git.cafe/gitcafe/zig/commit/4c1f71e866088a1a2e943331256115ed7e3daf98)

Repository: [gitcafe/zig](https://git.cafe/gitcafe/zig)

Visibility: public

Requested revision: 4c1f71e866088a1a2e943331256115ed7e3daf98

Requested commit: 4c1f71e866088a1a2e943331256115ed7e3daf98

Commit: 4c1f71e866088a1a2e943331256115ed7e3daf98

Tree: ff801e8aa7b5f1f578434198144c28a8350da6ed

Author: Cody Tapscott

Committer: Cody Tapscott

## Message

```
std.crypto: Optimize SHA-256 intrinsics for AMD x86-64

This gets us most of the way back to the performance I had when
I was using the LLVM intrinsics:
  - Intel Intel(R) Core(TM) i7-1068NG7 CPU @ 2.30GHz:
       190.67 MB/s (w/o intrinsics) -> 1285.08 MB/s
  - AMD EPYC 7763 (VM) @ 2.45 GHz:
       240.09 MB/s (w/o intrinsics) -> 1360.78 MB/s
  - Apple M1:
       216.96 MB/s (w/o intrinsics) -> 2133.69 MB/s

Minor changes to this source can swing performance from 400 MB/s to
1400 MB/s or... 20 MB/s, depending on how it interacts with the
optimizer. I have a sneaking suspicion that despite LLVM inheriting
GCC's extremely strict inline assembly semantics, its passes are
rather skittish around inline assembly (and almost certainly, its
instruction cost models can assume nothing)

```

## Parents

- [ee241c47ee675050e4e4b0eabd6ba06a82cc626e](https://git.cafe/gitcafe/zig/commit/ee241c47ee675050e4e4b0eabd6ba06a82cc626e?format=markdown)

[Source at this commit](https://git.cafe/gitcafe/zig/tree/4c1f71e866088a1a2e943331256115ed7e3daf98?format=markdown)